By Michael R. Bloomberg

Bold actions to protect the public's health always stir controversy at first. Smoke-free bars and restaurants, trans fat restriction and calorie posting in restaurants were all met with skepticism, but are now widely popular in New York City. They are also saving many lives each year, and life expectancy in New York City is outpacing that of the United States.

The initial reaction to our proposed portion cap on sugary beverages follows a now familiar pattern. But here are the key points. The increase in sugary drink consumption is the largest single cause of the rise in calories in the American diet in the last 40 years. Many studies show consumption of these beverages is linked to weight gain and obesity, and more recently, diabetes and heart disease.

Other studies show that people given larger portions simply consume more without noticing it or reducing calorie consumption at subsequent meals. And portion sizes of sugary drinks have ballooned drastically over the last 50 years, from 12 ounces to 32 ounces for a large beverage at a typical fast-food restaurant, not as a result of consumer demand but because of corporate decisions.

Together, these facts strongly suggest that if people are served smaller portion sizes of sugary drinks, they will consume less, gain less weight and be healthier ― and we may just start to reverse the catastrophic epidemic of obesity.

Critics claim this policy restricts choice. But, currently, people almost never have the choice to purchase as small as an 8-ounce beverage, which was considered adequate for decades.

Under our proposal, people could still choose to drink as much soda as they want. If 16 ounces (promoted as enough for three people in the 1950s!) is not enough, people could purchase two portions. Is that too much an inconvenience to reverse a national health catastrophe?

Rather than wringing our hands about the obesity epidemic, we in New York City are once again taking action to improve the lives of our residents. History will likely bear out that once the controversy dies down, we will look back and wonder why we did not do this sooner.

Michael R. Bloomberg is the 108th mayor of New York City. This article was published and distributed by USA Today.